(CNN) - If you ever find yourself hanging out on Antarctica's Danger Islands, we hope you like penguins. There's a lot of them there.
A previously unknown "mega-colony" of Adelie penguins have been found on the islands, which sit on Antarctica's northern tip.
More than 1.5 million of the birds were found in 2015 during a survey of the area, according to a report in the journal Scientific Reports.
Researchers estimate the Danger Islands hold the largest colonies of Adelie penguins in Antarctica and the third- and fourth-largest colonies in the world. Even more interesting, scientists think the penguins have flourished on the Danger Islands for decades, while other colonies of the birds have declined on other parts of the continent, especially on its western half.
So how were all those birds missed for all these years? Well, the Danger Islands are fairly remote, even by Antarctica standards. It's locked up in sea ice most of the year, and even in summer it's difficult to reach.
Special protection urged
But a boatload of researchers managed to get to the islands in December 2015, and they counted the penguins by manually counting individual nests and also counting nests using panoramic photos taken by drones.
Scientists are eager to study the birds, to figure out how they've managed to survive in such large numbers all of these years, while their numbers plummeted on other parts of Antarctica. It's believed climate change, including "changes in sea ice extent and concentration as well as changes in air temperature and precipitation patterns and their possible effects on prey availability" are the primary culprits for the decline in Adelie penguins in western Antarctica.
The researchers want the Danger Islands to receive some kind of consideration for special protection because of the large number of penguins found there.
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